Note that when configuring via System Settings / Network / Internet Settings, the dirty line will only be used when executing samples or URLs and the Firewall selected for the task is not the isolated firewall. It is very helpful to know your external IP address for both the dirty line and back end internet connections when running these tests.
For testing you should use a web page URL that will show you your external IP address. This will both confirm connectivity and show you that the right internet connection is being used. To give you fast results without waiting time, do not send files to MAA via Security Analytics or the Content Analysis System or other automated methods.
This example uses http://checkip.dyndns.org for URL task processing: